code: def identify_start_index_of_subsequence(subsequence, sequence):
      """find the location of the small tensor in the large tensor.
          e.g.  small = [1,3], large = [2,3,1,3], returns 2
                small = [3,2], large = [2,3,1,3], returns -1
      Args:
          small (tensor): small tensor
          large (tensor): large tensor
      """
      for i in range(sequence.size(0) - subsequence.size(0) + 1):
          if torch.equal(
              sequence[i : i + subsequence.size(0)], subsequence
          ):
              return i
      return -1
  
file_path: NeMo/nemo/collections/nlp/data/language_modeling/megatron/gpt_sft_chat_dataset.py
imports: import copy
  import torch
  from nemo.collections.common.tokenizers.tokenizer_spec import TokenizerSpec
  from nemo.collections.nlp.data.language_modeling.megatron.gpt_sft_dataset import GPTSFTDataset
  from nemo.utils import logging
label_desc: Use image node_id 3 for calling a global function with example usage: identify_start_index_of_subsequence(subsequence, sequence) and returns: unknown, i